This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A057389 #7 Mar 30 2012 16:48:52 %S A057389 1,0,0,0,0,0,3,0,0,0,9,18,-21,0,72,120,-45,-342,825,1296,-630,-2832, %T A057389 3411,21258,-6624,-40446,31338,209676,97677,-665712,152427,2666574, %U A057389 1655280,-6736512,-5070123,35432550,32647365,-83688480,-96328908 %N A057389 Low-temperature partition function expansion for hexagonal lattice (Potts model, q=4). %C A057389 The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice. %H A057389 I. Jensen, <a href="/A057389/b057389.txt">Table of n, a(n) for n = 0..60</a> (from link below) %H A057389 I. Jensen, <a href="http://www.ms.unimelb.edu.au/~iwan/potts/series/trp4pf.ser">More terms</a> %H A057389 G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/A2.html">Home page for hexagonal (or triangular) lattice A2</a> %Y A057389 Cf. A057374-A057405. %K A057389 sign %O A057389 0,7 %A A057389 _N. J. A. Sloane_, Aug 30 2000